MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1225 PM EDT FRI AUG 21 2015 VALID AUG 21/1200 UTC THRU AUG 25/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE SHORT RANGE FORECASTS. DEEP CYCLONE APPROACHING THE NORTHWEST LATE MONDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-CANADIAN COMPROMISE CONFIDENCE: ABOVE AVERAGE THE 00Z CANADIAN IS THE QUICKEST/MOST NEGATIVELY TILTED WITH THIS SYSTEM, WHILE THERE IS A STRONG CONSENSUS FOR A SLOWER, MORE POSITIVELY TILTED SOLUTION WHILE INCLUDES THE 06Z GEFS/00Z ECMWF ENSEMBLE MEAN SOLUTIONS. A COMPROMISE OF THE 12Z NAM/12Z GFS/00Z UKMET/00Z UKMET IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE. UPPER TROUGH/CYCLONE NEAR THE CENTRAL U.S./CANADIAN BORDER SAT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-GFS COMPROMISE CONFIDENCE: ABOVE AVERAGE THE 12Z GFS IS A BIT TO THE NORTH WITH THE CYCLONE'S CENTER AT THE SURFACE AND ALOFT. WITH THE SUPPORT OF THE 06Z GEFS/00Z ECMWF ENSEMBLE MEAN SOLUTIONS, PREFER A COMPROMISE OF THE 00Z ECMWF/00Z UKMET/00Z CANADIAN/12Z NAM WITH ABOVE AVERAGE CONFIDENCE. FRONT EDGING ACROSS NEW ENGLAND UPPER DISTURBANCE RETROGRADING ACROSS MEXICO ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE SHOWS GOOD AGREEMENT WITH THESE SYSTEMS. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH